Question

Mr. Lopez, Mrs. Manuel, Mrs. Manker and Mrs. Vo come to a river in the night. There is a narrow bridge, but it can only hold two people at a time. They have one torch and, because it's night, the torch has to be used when crossing the bridge. Mr. Lopez can cross the bridge in 1 minute,Mrs. Manker in 2 minutes, Mrs. Manuel in 5 minutes, and Mrs. Vo in 8 minutes. When two people cross the bridge together, they must move at the slower person's pace. The question is, can they all get across the bridge if the torch lasts only 15 minutes?[2]

Answer 1

To solve the puzzle, we need to find the optimal way for everyone to cross the bridge within the 15-minute limit.

1. Mr. Lopez and Mrs. Manuel cross the bridge together, taking 5 minutes.
2. Mr. Lopez goes back with the torch, taking 1 minute.
3. Mrs. Manker and Mrs. Vo cross the bridge together, taking 8 minutes.
4. Mrs. Manuel goes back with the torch, taking 5 minutes.
5. Mr. Lopez and Mrs. Manuel cross the bridge together again, taking 5 minutes.

In total, it takes 5 + 1 + 8 + 5 + 5 = 24 minutes for everyone to cross the bridge. Unfortunately, this solution exceeds the 15-minute limit for the torch. Therefore, there doesn't appear to be a way for everyone to cross within the given time constraint.